DE602004007630T2 - Stent and stent removal device - Google Patents

Abstract

A stent has an engagement member (9). A stent retrieval system has a tubular member (13) and a retrieval member (14) with an engagement means (15). The engagement member is attached to an end row of cells of the tubular stent body (1). The cells in one annular row of cells are interconnected with the subsequent row of similarly oriented cells (2a) at areas of interconnection (7) which in the subsequent annular row of cells are circumferentially offset with respect to the connections (8) between the cells in said subsequent annular row of cells. <IMAGE>

Description

The The present invention relates in a first aspect to a Stent and stent recovery system, the recovery system a tubular Member having a lumen terminating in a distal end opening and a recovery element comprising at least one engagement means, the tubular member and the recovery member are mutually axially displaceable while the recovery member in the lumen of the tubular Limb, the stent at least one engaging member, with which the at least one engagement means engageable is, and a tubular body from a plurality of annular cell rows comprises the interconnected and one after the other in the axial direction of the tubular body are arranged and the cells in an annular cell row with the following Row of equally aligned cells at mutual junctions connected in the subsequent annular cell row in Circumferential direction with respect to the connections between the cells offset in the successive annular rows of cells are.

Such a stent and stent recovery system is known WO 2004/008991 , where a stent is described having at one end larger cells that are not arranged in annular rows but instead in rows that extend only over one side of the stent. The cells in this end construction have a rather rough structure and in the end row, only a single cell is present, in which an engaging member can intervene.

The U.S. Patent No. 5,643,309 describes a stent provided with a number of inwardly projecting hooks at a distance from each end of the stent. The stent recovery system comprises an outer sleeve and a tubular member having an engagement ring secured to support legs on the outside of the tubular member and an inner recovery member slidably disposed in the tubular member. The recovery member is also provided with an engagement ring which is secured to support legs on the outside of the member. When the stent is to be removed from a vascular site, the sleeve is inserted into the stent and the tubular member and recovery member are both advanced out of the sleeve or tubular member so that both engagement rings have the opportunity to expand in the stent. The two engagement rings are brought into engagement with the two sets of hooks on the stent, and then the tubular member and the recovery member are moved in opposite directions so that the stent is extended to a greater length by the action of the rings on the hook. Due to the elongation of the stent, its diameter is reduced to such an extent that the stent is released from the vessel wall, and then the stent is withdrawn. The system is complicated and difficult to use.

EP 0 829 242 A1 and US 2002 0120277 A1 both describe a breast retrieval system having a tubular member with a lumen terminating in a distal end opening, and a recovery member having a plurality of engagement members formed as prongs with outwardly open hooks radially inward after insertion into a stent interior can be moved outwards into the wire mesh of the stent. When the recovery member is withdrawn, the hooks engage the wire mesh and pull the stent out to a greater length. As the stent is pulled longer, its diameter is reduced. The combination of the pulling action and the reduction in diameter cause the stent to be torn from the vessel wall.

in the U.S. Patent No. 5,910,144 For example, a plurality of gripper members can be moved to the position of a stent and have the ability to spread radially to a diameter greater than the stent diameter so that the gripper members can be slid on the outside of the stent. Then, the grippers are moved radially together, so that the stent is compressed to a smaller diameter and can be pulled out.

It in the first aspect of the present invention is an object of Invention to obtain a stent and stent recovery system, the safer recovery the stent offers.

to solution this object is the stent and Stentrückgewinnungssystem according to the claim 1, characterized in that the Zellendreihe an annular Cell row is where the single cell is an attachment point own that at least an engaging member comprises at least three wire sections, the are connected to each other at a connection point and themselves one by one from the connection point to the attachment point of an associated cell extend, and that the Attachment points in the annular Zellendreihe in the circumferential direction with respect to the compounds or mutual Junctions at the end of the tubular body between the cells in the end row are offset.

The at least three wire sections in the engagement member form a strong and properly distributed handle in the first row of cells at the end of the tubular body. By attaching the one handle member on the annular end row of cells at points which are circumferentially offset with respect to the connections between the cells in the series, a pulling action in the engaging member causes a deformation of the cell sides extending between the individual attachment point and the adjacent connections between the cells extend. The initial pull pulls the male member toward and into the tubular member, and upon further pulling, the male member is drawn into the lumen of the tubular member and the end row of cells is brought into abutment with the edge of the aperture. When the engaging member is pulled into the lumen, it acts on the cell end row and causes some deformation thereof. Since these deformations act locally and only on the end side of the annular cell row, this cell row radially collapses to a smaller diameter at the end side but retains almost the initial diameter on the opposite side of the annular row.

The collapsed end side can be radially down to and into the distal end opening be pulled by pulling the engaging member. When this happens is, the cell sides are rotated in the cell end row and / or bent inwardly at an angle that gets bigger when the end side is pulled down to a smaller diameter. This movement pattern The cell side is very beneficial, especially if the stent from a vascular site should be removed, where he temporarily positioned for a desired period was because the vessel wall only a minimal damage added becomes.

If a stent in a vessel, e.g. a blood vessel tissue forms around the stent material within a few days. Such tissue ingrowth allows the stent to become integral Become part of the vessel wall. The ingrowth leads to a layer of tissue called intima, on the inside of the stent. If a stent using the prior art techniques of Stent removal is removed, where the diameter of the stent is reduced by pulling the entire stent to a greater length, affects the ripping off from the intima to a big one Area of the vessel wall, and the dangers of damage the vessel wall are big. If the vessel is weak is what often the case exists at sites where a stent is applied even a very high risk of tearing the vessel, though the stent is removed. With the present invention is recognized been that that Tear off by an axially directed train in the stent in conjunction with a Radial contraction can be caused on a substantial Length of the Stents works.

Of the Stent according to the present invention is not subject to any significant axial pull during the Distance. The pulling in the engaging member only has to be sufficient Side of an annular Pull down cell line. When this pulling is done, the vessel wall stays supported by all remaining cells in the annular rows that are not yet in the tubular Member have been moved into it. The stent is thus axially stationary in relation held on the parts of the vessel wall, the to be in contact with the stent. The ring-shaped cell line, which is located in the Process of radially pulling down into the tubular member is in, is released in a gentle way from the vessel wall. This This is because only one side of the series is initially freed from the vessel wall and then the cell material gradually towards the others Side of the series due to which is cleared that the Cell material in the vessel turns inwards or bends. When one side of the annular row into the distal end opening has been moved, the tubular member is forward in the direction the other side of the annular Pushed row, which is located on the subsequent annular cell row.

During this Pushing the tubular Limb enters the cell material into the distal end opening, and then the other side of the annular row goes down pulled a smaller diameter and thereby becomes the cell material pulled radially inwards and out of the vessel wall. Then the Repeat process with the following annular cell rows. The mutual connection areas between a row and the subsequent rows are circumferentially with respect to the joints offset between the cells in the next row. A drawing in leads to mutual connections to a deformation of the cell sides, which are between the individual Attachment point and the adjacent connections between the Cells extend. Because these deformations are local and only to the end of the annular Cell series act, this cell row puts radially on a smaller Diameter on the end side together, but remains almost to Initial diameter at the opposite Side of the annular Line. Then, the tubular Link forward to the next annular Row are pushed. The procedure is repeated until the stent Completely in the tubular Limb is placed and then the recovery system is out of the vascular system withdrawn.

The breast retrieval system may also be used to position a stent in the tubular member from an unloaded stent condition prior to placing the stent in a patient. In other words, the recovery system may be a system for inserting a Stents are used in a tubular member, such as an insertion system.

at an embodiment is the single attachment point in the circumferential direction approximately at the center located between two adjacent connections. In such a Position the cells in the end row evenly over the Attachment points together. It is of course possible, too not preferred, the attachment points in an asymmetrical manner with respect to the adjacent connections.

at a further embodiment is the single connection area with a subsequent annular row in the circumferential direction approximately in the middle between two adjoining Arranged connections. In this arrangement, the cells lie down in the following row evenly over the connection areas together. It goes without saying also possible, but not preferred, the connection areas in asymmetric form with respect to the adjacent connections.

at a preferred embodiment form the first cell sides in the single annular cell row at least one circumferentially closed loop, in the the first cell sides forming the loop are in directions, the angles range from 60 ° to 120 ° with the axial direction of the tubular body form when the tubular body itself is in an unloaded condition. The closed loop gives the stent a high rigidity against radial compression and thus good properties for keeping open a vessel. even in places where the vessel has a bend shows, but more important is that the closed loop in high mass has the ability to their initial diameter uphold if a local Train is applied in the adjacent cell material. If the angle deviates from 90 ° by more than 30 °, For example, the tendency to maintain the initial diameter may become weak. It is preferred that the Angular range in the range of 70 ° to 110 °, because the ring-shaped cell line then only to a small extent a larger diameter receives when the first cell sides are pulled towards the distal opening become. When the angle range is limited to the range of 75 ° to 105 ° is, the train can be kept constant in the engaging member.

at an embodiment connect second cell sides in the single annular cell row the circumferentially closed loops with each other and run at least along part of its length in a direction that Angle in the range of 20 ° to 70 ° with forms the axial direction of the tubular body, when the tubular body is in an unloaded condition. The flexibility of the second Cell sides and the width of each annular row are relatively good Balanced when the angles are in the specified range. The range is preferably 30 ° to 60 °.

Preferably The first cell sides are substantially in a radial Level at the distal end opening of the tubular Limb, when the second cell sides in the adjacent annular cell row through the distal end opening have been retracted to from the distal end opening in the tubular Extending link. When the first cell pages rotate like this or can bend that she in or about in a radial plane, when the second Cell sides through the distal end opening have been pulled, then the tubular body can its initial Diameter for as long as possible maintained.

Prefers will that the Outside diameter of following loop outside of the tubular Member essentially unimpaired stays while a loop into the distal end opening is involved. Since the subsequent loop is not affected, becomes the vessel wall the subsequent loop in turn not affected.

Of the Connection point of the engagement member is preferably on the longitudinal central axis of the tubular body arranged. By arranging the connection point on the central axis becomes the manufacture of the engagement between the engaging means and the engaging member easier accomplished. The train in the engaging member is also more uniform the attachment points distributed when the connection point on the Center axis lies where the connection point symmetrical with respect is positioned on the cell end row.

In a particularly preferred embodiment, the wire sections have a length such that the connection point is at least 0.5 × W apart from the annular cell row at the end of the tubular body, where W is the width in the axial direction of the annular cell row. By positioning the connection point at such a distance from the end loop, this loop is exposed to primarily radially acting forces as the connection point is retracted through the distal end opening because the wire sections bend in the area in front of the opening before the wire sections are drawn into the lumen , The bent wires gradually pull the attachment points radially inward as the tubular member is slid toward the end loop until the attachment points at the distal end opening are at a mutual radial separation corresponding to the inside diameter of the lumen in the tubular member.

at an embodiment comprises the at least one engaging member magnetic material. The engaging member can e.g. made of ferromagnetic material, which is a magnet attracts or it can be a magnet with one polarity, which points in a certain direction, such as in the axial direction or the radial direction of the tubular body. In the case that the magnetic Material a polarity owns, this polarity can opposite to the polarity be a magnetic material at the engaging means So that the Engaging device is attracted to the engaging member. A Such attraction effect can also be with a magnet on a Part of engaging member and engaging means are achieved if the other of the two parts is made of ferromagnetic material. The purpose of the magnetic materials is to manufacture to facilitate the engagement in the engaging member when this is inside a vessel lies.

The inner lumen of the tubular Limb may have a diameter in the range of 20% to 80%, preferably from 30% to 60% of the outside diameter of the tubular body have in the unloaded state of the tubular body. Although it possible is a tubular Link with a lumen of less than 20% of the outer diameter of the tubular body use, no advantage is achieved, but on the contrary the lumen becomes so small that it can be more difficult to accommodate the tubular body in the lumen. The upper limit of 80% is sufficient, a complete release of the stent from the tubular wall to reach. The preferred range of 30% to 60% brings the Advantage with that more Space in the lumen and a relatively smaller one Outer diameter of the tubular Link is present, thereby introducing the Stentrückgewinnungssystems through the vascular system to the stent position is facilitated.

at an embodiment is the tubular one body with at least one extra Means provided that selected is from the group of a medically active substance, one of the Proliferation of a tumor cell-inhibiting bioactive factor, a bioactive substance, a bioactive agent, a drug and a coating for controlled delivery of one or more bioactive materials, a medically active substance or a bioactive factor. The bioactive substance or the bioactive Agent can e.g. to be of a texture that negatively influences of Stent reduced to the vessel wall, or of a texture that effects the introduction a stent into the vascular system strengthened. Instead, the stent may be used as a carrier for inserting the Substance, the agent, the factor or the drug to a vascular site be used where a local Release the substance, the agent, the factor or the drug required becomes. The stent will be in place in the vascular system in the required amount of time to obtain the desired Releasing the substance, the agent, the factor or the drug at the vascular site and then the stent is made using the stent retrieval system away. The stent recovery system is particularly advantageous for such an application because of the very gentle removal process, in which the stent material is released from the vessel wall, without or almost without that the Vessel wall essential forces is exposed, which are directed in the axial direction of the tubular body. The annular ones Cell lines are separated from the vessel wall by the mainly radial ones Merging the rows solved. The vessel wall is often very weak in the places where a local release of drugs etc. is required. The weakening can e.g. caused by the presence of tumor cells near the vessel wall be. Because of the gentle removal of the stent are the dangers the damage through the vessel wall the distance is reduced to a minimum. It is therefore possible, even very weak vessel sites to treat with a temporary stent, which was previously not possible is.

at an embodiment has the extra Means a predetermined active period in the range of three days up to one month, preferably from 5 to 14 days. The waxing an intimal layer on the inside of the stent increases with the duration of the introduction. Because of the gentle distance The stent will make it possible vascular site for one longer Period, about up to a month, to treat and still use the stent without intolerable damage to the vascular site to remove.

It is possible, the tubular body with a tubular Cover, such as a fabric of graft material to provide. The cover may serve to stent with a larger surface area to equip what may be beneficial, inter alia, in cases in which larger quantities a drug or a bioactive substance or a bioactive substance Agent of the vascular site supplied must become. The cover may also be required to provide temporary closure of a Branch vessel, one To get aneurysms or other vascular malformation.

The stent can be inserted into the tubular member easily and without the use of complicated additional equipment the.

If the stent in the tubular Link is to be introduced, the engaging member is first in the Lumen of the tubular Member in and pulled through this, and the tubular member is to the tubular body pushed through, causing the annular Cell rows for the final opening brought up and one after the other at the end opening merged a state with radially reduced diameter be while the annular ones Cell rows their initial At least maintain the diameter until it is within one Row from the end opening are.

The forces which are required for moving the stent into the tubular member, are very low, because the forces mainly on the annular Act cell row, which is positioned immediately in front of the tubular opening. If the cell sides in the annular Row pulled against the edge of the opening these cell sides are deflected under the effect of the edge, to align with the inner lumen in the tubular member. During the Continued train in the engaging member align the cell sides even on the radially reduced diameter according to the inner lumen in the tubular New member. Then the tubular member can be pushed towards the stent so that the Edge of the end opening to the other side of the annular Cell row is moved. While this movement becomes the inner cell sides of the annular row introduced into the lumen, and because of the smaller diameter of the Lumens cause these inner cell sides an increasingly strong radially directed Pulling in the cell sides on the opposite side of the annular cell row, so that this Cell sides get away from the next annular cell row with the initial diameter of the stent and radially narrower inward spaced locations at the end of the inner lumen of the tubular member to extend. Then, the method with the next annular cell row be repeated.

There There is no need for complicated equipment can use to introduce the stent in the tubular member can the insertion takes place just before the stent is used should. This offers the major advantage of the possibility Preparation of the stent with a coating of active Properties of temporary effect. If the active property the coating only e.g. 7 or 14 days, then go Effects during lost storage of the stents produced. By attachment the coating on the stent just before the stent is used should, and by introducing the coated stent into the tubular member in the manner indicated above, the stent is ready to use without every decrease in the active property.

The The invention will be described in detail below with reference to exemplary embodiments explained with reference to the schematic drawing, in the

1 is a plan view illustrating the cell structure used in one embodiment of a tubular body of a stent according to the invention,

2 a side view of the stent with a cell structure as shown in FIG 1 shows,

3a to 3d Side views of successive steps of the stent 2 when drawn into a tubular member using a return system,

4 a cross section along the line IV-IV of 3e shows, seen from the left side of the 3e , and

5 a plan view corresponding to the view of 1 another embodiment of a stent according to the invention, which is made by laser cutting or etching in a tubular member.

The 1 and 2 illustrate the structure of a stent according to the invention, wherein the stent is in the unincorporated state. The stent consists of wires which are bent according to a pattern for forming a tubular body, cf. 2 , For simplicity, the cell pattern is in 1 illustrated in a cut, unfolded state of the stent. The pattern is of annular rows of arrowhead-like and heart-shaped cells, respectively 2a formed, wherein the rows are interconnected and one after the other in the axial direction A of the tubular body 1 are arranged. The annular rows of cells 2a have the same orientation in the tubular body. Between these rows of cells lie cells 2 B with opposite orientation in the axial direction, ie, the arrowhead or the apex of the head points in the opposite direction.

Every cell 2a has two first cell pages 3 that converge toward each other to one another in a connection area 8th between the cells 2a in a row and the cells 2a to be connected in the subsequent annular row. The first cell pages 3 form a circumferentially closed loop on each end side of the annular cell row 20 , in which the first cell sides are at an angle α of about 107 ° with respect to the axial Rich tion A extend. Every cell 2a also has two mutually converging second cell sides 4 that con verg to each other in mutual connections 7 between the cells 2a to be connected in the annular row. The second cell sides 4 connect the loops 20 on each side of the annular row of cells 2a , The second cell sides 4 extend in a direction which forms an angle β of about 38 ° with respect to the axial direction A. In other embodiments, the indicated angles may take different values. The angle α can be, for example, in the range of 60 ° to 120 ° and the angle β, for example, in the range of 20 ° to 70 °.

The cell sides 3 lie on the cell sides 4 the cell opposite, and the cells 2a Each cell row is connected by means of compounds 7 connected, forming the loop-shaped nodes. The mutual connection areas 8th , which connect an annular cell row with the next cell row, form a node formed by once wound around wires. In the embodiment shown, the compounds 7 and the connection areas 8th offset in the circumferential direction with a distance substantially the circumferential extent of one of the cell sides 3 equivalent.

2 shows the tubular body 1 of the stent. An intervention member 9 is at a cell end row 12 attached to the left end of the tubular body 1 lies. The engaging member 9 is formed by four wire sections, which together at a Verbindungspnkt 10 connected on the longitudinal central axis of the tubular body 1 lies. The single wire section is connected to the tubular body 1 at an attachment point 11 connected, with the attachment points 11 in the circumferential direction with respect to the connections 7 at the end of the tubular body 1 are offset at a distance substantially the circumferential extent of one of the first cell sides 3 equivalent. This brings every single attachment point 11 on the middle of the cells 2a between the two adjacent connections 7 in the circular cell row 12 at the end of the tubular member 1 , The wire sections have a length such that the connection point 10 about 1.0 × W from the loop of the cell end row 12 at the end of the tubular body 1 where W is the width of a row of cells in the axial direction of the tubular body.

The 3a to 3d show successive stages of the stent 2 which is in a tubular body 13 a recovery system according to the invention is recovered. A recovery element 14 is slidable in the lumen of the tubular member 13 arranged and has a greater length than the tubular member so that it can protrude from both the distal end and from the proximal end from which it is handled. The recovery member is provided with an engagement means in the form of a hook 15 provided at its distal end. The recovery member consists for example of steel or other material of sufficient strength.

The tubular member 13 extends at its distal end in a distal end opening defined by an annular end surface 16 is formed on the tubular member. In the illustrated embodiment, the diameter of the tubular member corresponds 16 about 55% of the initial diameter of the tubular body 1 when the latter is in the unpacked (relaxed) state.

To 3a is the recovery element 14 the recovery system with the wire sections of the engaging member 9 at the connection point 10 by means of the hook 15 engaged around the wire sections. In the illustration, the engagement member to the tubular member is pulled to a position in which the wire portions at the annular end surface 16 of the tubular member abut. The tubular body remains visible even in its unincorporated state.

The 3b to 3e show how the third row of cells in the tubular member 13 is involved. In 3b has the catch 15 the engaging member 9 and two rows of cells in the tubular member 13 of the recovery system, and the loop 20 on the proximal side of the third annular cell row lies at the annular opening. The mutual connection areas 8th , which connect the second and third rows of cells with each other, are inward to the central axis of the tubular body 1 have been pulled and have just the annular end face 16 happens and are in the end opening of the tubular member 13 occurred. These are the second cell sides 4 the second cell row, the inward connecting portions of the second cell row inwardly to the central axis of the tubular body 1 have drawn, with the first cell sides 3 the third cell row are bent inwards.

As seen from the presentation 3b can be seen, are the second cell sides 4 the third cell row slightly deformed. Thus, the further pulling in the recovery member 14 to that the first cell sides 3 and the connections 7 the third row of cells pulled radially downwards and through the end opening of the tubular member 13 come in, cf. 3c and 3d , It should be noted that in the 3b to 3d the fourth cell-row remains unaffected by the merging of the third cell-row, and therefore has not yet begun to fuse.

Once the connections 7 in the loop 20 at the proximal side of the third annular row have been drawn into the distal end opening of the tubular member, the tubular body 13 to the right side of the figure, ie in the direction of the tubular body, to be moved. During this displacement of the tubular member, the second cell sides become 4 in the third annular row is moved into the lumen of the tubular member while reducing the diameter of the cells for lumen correspondence.

In 3e the tubular member is advanced so far that it has the distal end opening near the proximal end loop 20 the fourth annular cell row, wherein the first cell sides 3 bend the fourth row of cells inwards and start, the fourth row of cells into the tubular member 13 implicate. The in 3b to 3e The process illustrated with respect to the third cell row is then repeated for the fourth cell row, and so on for subsequent cell rows, until the entire stent lies inside the tubular body.

In 4 is the initial merging of the fourth cell row worked out, the representation of a cross section along the line IV-IV of 3e , seen from the left side of the 3e , shows. In 4 are the first cell pages 3 The proximal loop in the fourth cell row partially collapsed and extend from the mutual connection areas 8th in the interior of the tubular member 13 and out to the links 7 , The first cell pages 3 The fourth row of cells are bent so that they form curved shapes that form a flower-like form with four leaves. The fifth cell row is still in its initial state, and the first cell sides 3 the fifth row of cells run along the contour of the larger outer circle of the drawing.

The The engaging member on the stent may have other shapes than those shown above accept. It can e.g. formed in the form of a plurality of crossing wires It may have one or more flexible wires at the end of the stent are attached, or it can be used as loops or eyelets or thighs be formed, extending from the circumference of the annular Zellendreihe and radially or at an angle in to the centerline of the tubular Body extend. The engaging member may be a magnet or magnetic material include. The engaging member on the recovery member may also be provided with a plurality of hooks, or it may be a gripper device, a tongue, an eyelet or a cord attached to one or more engaging members of the tubular body to attach. What matters, is that the Engaging means can be spent in a state in which the Retrieval member with a tensile force on the engaging member on the tubular body or on the tubular body can act.

5 Figure 11 illustrates another embodiment of a stent according to the invention formed by laser cutting or etching a tubular member, the stent corresponding to an unfolded state 1 for illustration purposes. In 5 have parts that are similar to the previous representations, have been given the same reference numbers. The operation of the embodiment according to 5 essentially corresponds to the embodiment described above. In the embodiment according to 5 the connections 7 between the cells 2a . 2 B and the mutual connection points 8th , which connect successive cell rows with each other, formed as S-shaped connections. This causes the compounds 7 and the mutual connections 8th are substantially similar to the previously described embodiment. The cells in the tubular body may have cell patterns other than those described. The cell sides can, for example, have a wavy course and they can have unequal widths or a width varying over the length of the cell side.

The Number of cells in each annular cell rows may vary from the current cell shape and the diameter of the tubular body in vary in its unloaded condition. To give an example can four cells with uniform alignment in an annular row be there, it can but also three cells or more than four, about five, six or seven cells be with the same orientation.

Of the Diameter of the tubular Body in unloaded condition may vary with the application of the stent. For one For use in arteries, the stent may e.g. a diameter in the Range from 0.5mm to 3mm when in small arteries or veins, say in the brain, it can be a diameter in the range of 2 mm to 4 mm for have coronary use or pancreatic uses, and may range in diameter from 6 mm to 12 mm for iliac, femoral, renal and carotid uses, etc.

Of the Stent can also be with a cover on a part or on the entire peripheral surface of the tubular body be provided. The stent can be made of nitinol threads, such as a round or flat thread, be made of stainless steel, titanium, tantalum, platinum, Composites or synthetic materials.

In one embodiment, the stent is provided with a bioactive material, such as heparin or another thrombin inhibitor, anti-inflammatory steroids including, but not limited to, dexamethasone and its derivatives and mixtures of heparin and such steroids. The bioactive material or agent may also be an antiproliferative agent such as methotrexate. For example, the stent may be inserted into the arterial supply of the tumor to provide an agent that delivers a relatively high dose of the antiproliferative agent directly to the tumor. The bioactive material may further be a vasodilator such as a calcium channel blocker or a nitrate. The stent may also be provided with a drug such as a cytostatic chemotherapeutic agent for delivery to a localized tumor, for example, tamoxifen citrate, Taxol or derivatives thereof Proscar ^{®, ®} Hytrin, or Eulexin ^®. Dopamine or a dopamine agonist such as bromocriptine mesylate or pergolite mesylate may be cited as examples of drugs for other purposes. The stent may also be provided with a factor which provides antiproliferative activity against cells. Such factors or compositions may be, for example, a cytotoxic / cytostatic, antiproliferative factor. Typically, a pharmaceutically acceptable form of antiproliferative factor or a functional analogue 04 thereof can be used.

details the above embodiments can with other embodiments within the framework of the attached claims be combined. The cell shapes do not have the special in have the type shown in the drawing, since the scope of the claims other cell shapes comprises as approximated rectangular cells, cells in which the connections between the Cells in the individual cell rows mainly or completely in axial direction of the tubular body and the cell sides (the above-mentioned first cell sides), the form circumferentially closed loops, in directions run the angles of at least 92 ° or less than 88 ° with the Axial direction of the tubular Form body. The cells can also polygonal, about hexagonal, or the first cell sides in the circumferentially closed loops, a wavy Have shape or a meander shape form.

Claims (16)

Stent and Stentrückgewinnungssystem, wherein the recovery system is a tubular member ( 13 ) with a lumen terminating in a distal end opening and a recovery element ( 14 ) with at least one intervention means ( 15 ), the tubular member ( 13 ) and the recovery member ( 14 ) are axially displaceable relative to one another while the recovery member extends into the lumen of the tubular member, the stent comprises at least one engagement member ( 9 ), with which the at least one engagement means can be brought into engagement, and a tubular body ( 1 ) of a plurality of annular rows of cells connected to each other and arranged one after the other in the axial direction of the tubular body and the cells ( 2a ) in an annular cell row with the subsequent row of cells aligned in the same way at mutual connection points ( 8th ) connected in the subsequent annular cell row in the circumferential direction with respect to the compounds ( 7 ) between the cells in the successive annular rows of cells, characterized in that the cell end row ( 12 ) is an annular cell row in which the single cell ( 2a ) an attachment point ( 11 ) has that the at least one engaging member ( 9 ) comprises at least three wire sections which are interconnected at a connection point ( 10 ) and individually from the connection point ( 10 ) to the attachment point ( 11 ) of an associated cell, and that the attachment points ( 11 ) in the annular cell end row ( 12 ) in the circumferential direction with respect to the compounds ( 7 ) or mutual connection points ( 8th ) at the end of the tubular body ( 1 ) between the cells in the end row ( 12 ) are offset. Stent and stent recovery system according to claim 1, characterized in that the single attachment point ( 11 ) in the circumferential direction approximately in the middle between two adjacent connections ( 7 ) or mutual connection points ( 8th ) lies. Stent and stent recovery system according to claim 1 or 2, characterized in that the respective mutual connection point ( 8th ) in the circumferential direction approximately in the middle between two adjacent connections ( 7 ) lies. Stent and stent recovery system according to one of claims 1 to 3, characterized in that the first cell sides ( 3 ) in the single annular cell row at least one circumferentially closed loop ( 20 ) in which the first cell sides forming the loop extend in directions which angle (α) in the range of 60 ° to 120 °, preferably in the range of 70 ° to 110 ° and expedient in the range of 75 ° to 105 °, with the axial direction (A) of the tubular body ( 1 ) when the tubular body is in an unloaded state. Stent and stent recovery system according to claim 4, characterized in that second Cell pages ( 4 ) in the single annular cell row the circumferentially closed loops ( 20 ) and extend in at least part of their length in directions, the angles (β) in the range of 20 ° to 70 °, preferably in the range of 30 ° to 60 °, with the axial direction (A) of the tubular body ( 1 ) when the tubular body is in an unloaded state. Stent and stent recovery system according to claim 4 or 5, characterized in that the first cell sides ( 3 ) substantially in a radial plane at the distal end opening of the tubular member (Fig. 13 ), when the second cell sides ( 4 ) have been retracted in the adjacent annular cell row through the distal end opening to extend from the distal end opening into the tubular member (FIG. 13 ) extend into it. Stent and stent recovery system according to any one of claims 4 to 6, characterized in that during the loop ( 20 ) is pulled into the distal end opening, the outer diameter of the subsequent loop ( 20 ) outside the tubular member ( 13 ) remains unaffected. Stent and stent recovery system according to one of claims 1 to 7, characterized in that the connection point on the longitudinal central axis of the tubular body ( 1 ) lies. Stent and stent recovery system according to claim 8, characterized in that the wire sections have a length such that the connection point ( 10 ) at least 0.5 × W away from the annular cell end row ( 12 ), where W is the width in the axial direction of the annular cell rows. Stent and stent recovery system according to one of the claims 1 to 9, characterized in that the at least one engaging member includes magnetic material. Stent and stent recovery system according to claim 10, characterized in that the magnetic material a polarity that has the polarity opposite to a magnetic material located on the engagement means is. Stent and stent recovery system according to one of claims 1 to 11, characterized in that the inner lumen of the tubular member ( 13 ) has a diameter in the range of 20% to 80%, preferably 30% to 60%, of the outer diameter of the tubular body ( 1 ) in the unloaded state of the tubular body. Stent and stent recovery system according to one of claims 1 to 12, characterized in that the tubular body ( 1 ) is provided with at least one additional agent selected from the group consisting of a medically active substance, a tumor cell proliferation inhibiting bioactive factor, a bioactive substance, a bioactive agent, a drug and a cover layer for the controlled release of one or more bioactive materials, medically active substance or a bioactive factor. Stent and stent recovery system according to claim 13, characterized in that the additional means a predetermined Duration of action in the range of three days to one month, preferably from 5 to 14 days, owns. Stent and stent recovery system according to one of claims 1 to 14, characterized in that the tubular body ( 1 ) is provided with a tubular cover. Stent and stent recovery system according to one of claims 1 to 15, characterized in that in the annular cell end row ( 12 ) from the attachment point ( 11 ) outgoing first cell pages ( 3 ) an angle on the side of the attachment point ( 11 ) of less than 88 ° with the axial direction of the tubular body when the tubular body is in an unloaded state, and that the connections between the cells in the single cell row in the axial direction of the tubular body ( 1 ).